* City into FA Cup final for first time since '81
* Yaya Toure grabs only goal at Wembley
* United's treble hopes dashed (adds details)
Manchester City reached the FA Cup final for the first time since 1981 after a dramatic 1-0 win over arch rivals Manchester United who finished with 10 men after midfielder Paul Scholes was sent off 18 minutes from time.
The winner came from Yaya Toure eight minutes into the second half at Wembley after he capitalised on some poor defending to end United's hopes of repeating their 1999 treble of Champions League, Premier League and FA Cup.
City, who started slowly but finished far the better team will now face Bolton Wanderers or Stoke City, who meet in their semi-final at Wembley on Sunday with the final on May 14.
United started the stronger side and should have scored after 15 minutes when Dimitar Berbatov had two chances inside 60 seconds but wasted both, while City weathered the early pressure and took control of the match for much of the last hour.
United's miserable day ended when Scholes was sent off after 72 minutes for a high challenge on City defender Pablo Zabaleta.
Tempers flared after the final whistle when a dispute between City striker Mario Balotelli and United midfielder Anderson resulted in United defender Rio Ferdinand having to be restrained by team mates as he tried to confront Balotelli.
Alex Ferguson's side were favourites but had to cope without in-form Wayne Rooney who was suspended, while City were missing their captain and most dangerous player Carlos Tevez who pulled a hamstring in the 3-0 loss at Liverpool on Monday.
Both teams began sluggishly but United were the first to come to life with two chances for Berbatov in the 15th minute.
The first followed a brilliant exchange of passes between Michael Carrick, Scholes and Park Ji-sung that opened the City defence to release Berbatov whose shot was saved by Joe Hart.
Twenty seconds later Berbatov missed from close range after a fine cross from Nani.
City made little impact in the opening 25 minutes as United began to press with Park, Scholes, Nani and Antonio Valencia in total control of the midfield.
But the balance of the game began to change midway through the half and City's first chance came after 32 minutes when Gareth Barry, who had been largely anonymous like most of his team mates up to then, saw his shot hit the the side netting.
That seemed to belatedly spark his side into life and City finished the half looking much the better team.
Two minutes after Barry's effort, Balotelli shot from 35 metres forcing Edwin van der Sar into a fine save before Joleon Lescott, in space at a corner, struck a volley over the bar.
Yaya Toure and Aleksandr Kolarov also went close -- and City maintained their dominance after the restart.
The goal came when Van der Sar made a rare poor clearance and Carrick played a lazy pass that was intercepted by Toure who whipped the ball away and powered down on goal before lashing the ball through Van der Sar's legs for the opener.
City continued to control the game and appeared to take an even stronger grip when the fiery Scholes was shown a straight red card for a high lunge at Zabaleta.
United who began so well, hardly created a chance for an equaliser apart from a Nani free-kick which Hart tipped on to the bar and City were left to celebrate their derby win.